Liquid high-tension switch with tubelike electric arc-quenching channels

ABSTRACT

Circuit breaker having a quenching chamber in which a movable contact member is moved from a first position electrically connecting two stationary contact members to a second position for electrically disconnecting such stationary contact members; electric arcs being formed in one general direction between the movable and stationary contact members during such movement of the movable contact member. The movable contact member being moved by means of introducing a stream of arc-quenching fluid in a direction transverse to the direction in which such arcs are formed. Such arcs being driven by the arc-quenching fluid into a plurality of tubelike channels extending in the direction of movement of the movable contact member where the arcs are quenched.

United States Patent [72] Inventors Dieter Kind Braunschweig; Erwin Marx, Braunschweig; Jurgen Salge, Salzgitter-Osterlinde; Klaus Mollenhoff, Braunschweig, all of, Germany [21] Appl. No 757,044

[22] Filed Sept. 3, 1968 [45] Patented June 29, 1971 [73] Assignee Dieter Kind by said Marx, Mollenhoff and Salge [32] Priority Aug. 31, 1967 [33] Germany [31] P 16 40 720.8

[54] LIQUID HIGH-TENSION SWITCH WITH TUBELIKE ELECTRIC ARC-QUENCHING [56] References Cited UNITED STATES PATENTS Primary Examiner-Robert S. Macon Attorney-Spencer and Kaye ABSTRACT: Circuit breaker having a quenching chamber in which a movable contact member is moved from a first position electrically connecting two stationary contact members to a second position for electrically disconnecting such stationary contact members; electric arcs being formed in one general direction between the movable and stationary contact members during such movement of the movable contact member. The movable contact member being moved by means of introducing a stream of arc-quenching fluid in a direction transverse to the direction in which such arcs are formed Such arcs being driven by the arc-quenching fluid into a plurality of tubelike channels extending in the direction of movement of the movable contact member where the arcs are quenched PATENTEDJUNZSIHYI 3.590191 SHEET 2 [IF 3 Fig. IO

INVENTORS Dieter Kind Erwin Marx Jiirqen Solge 8 Klaus Miillenhoff BY My )QZ ATTO NEYS PATENTEU JUH29|9H 3,590,191

SHEET 3 [1F 3 INVENTORS Dieter Kind Erwin Mcarx Jiirqen Solge 8 Klaus Mbllenhoff BY g W22 ATTORNEYS LIQUID HIGH-TENSION SWITCH WITH TUBELIKIE ELECTRIC ARC-QUENCI'IING CHANNELS BACKGROUND OF THE INVENTION The present invention relates to an electric circuit breaker, particularly to a liquid switch, having an electric arcquenching chamber and means for artificially producing a quenching medium flow transverse to the direction in which the electric arc originates.

Circuit breakers of the type to which the present invention relates are known for interrupting alternating currents as well as direct currents at high voltages. One known circuit breaker uses a stream of oil under high pressure which subjects the electric arc created during the cutoff process to a strong transverse stream in a vent-type portion of the quenching chamber which is provided with numerous outlet openings. This transverse flow leads to an electric arc voltage which counteracts the driving voltage so that the current becomes zero and the circuit is thus interrupted.

The present invention is based on another type of circuit breaker which provides a high electric arc voltage, i.e. by means of a greatly extended electric arc. Known circuit breakers of this type operate mostly with a greater number of adjacent vent-type chambers into which the electric arc is driven in numerous loops thus to be cooled. The electric arc is driven in such circuit breakers under the influence of a magnetic field.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved circuit breaker in which'an electric arc is more effectively quenched.

The switch according to the present invention differs from magnetic blowout switches in that a strong extension of the circuit breaking electric arc is effected by a very rapid flow of the quenching medium.

According to the invention, there is provided a connecting bridge or movable contact member between two stationary contact members; the movable contact member being moved by a stream of quenching medium. The partial arcs created at the movable contact member as a result of its movement away from the stationary contact members are driven into two or more tubelike outlet channels for the quenching medium. These channels extend in the direction of movement of the quenching medium and the direction of movement of said movable contact. The quenching medium stream, which is under high pressure, can be produced, for example, by means of a hydropneumatic storage container or by a propellant which acts on an acceleration piston for the quenching medium. In either case the quenching medium stream causes the movable contact member to perform a quick cutoff movement and the partial electric arcs created are driven into the longer tubelike outlet channels and are there, in the only outlet for the quenching medium, subjected to concentrated quenching. By this arrangement, the electric arcs are thus considerably lengthened so that a significant arc voltage is created which even at high currents in the range of KA can reach up to 1,000 volts per tubelike outlet channel as determined by measurements.

Since the outlet channels are disposed directly at or around the movable contact member, relatively little space is required for the extinction of the arc. Therefore, it is possible to house a plurality of serially arranged circuit breakers connected by conductive paths within a housing of relatively small dimensions.

Another feature of the present invention, which provides a more effective cooling of the electric are by the flow of quenching medium, is realized when the cross section of the tubelike outlet channels discussed above is enlarged in the originating direction of the electric arcs and/or in the direction of the flow of the quenching medium. By a further aspect of the present invention, it has been proven ad vantageous to arrange the outlet openings of the outlet channels in different directions in order to facilitate the prevention of a sparkover from one outlet channel to the other in case the arc should jump out of the outlet channels.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT According to FIG. 1, the movable contact member 1 is in the cutoff position or the second of two operational positions. In this position, it is under the influence of a spring 2 which, upon completion of the intake of quenching medium, returns it to the switch-on position, or the first of the two operational positions, there to make contact with the stationary contact members, switching components 3 and 4. The quenching medium flows for a short time after the signal for cutoff is given, via a nozzle-type bore 5. The quenching medium flows into the switching path and pushes the movable contact member 1 against the force of spring 2. The electric arcs 6 and 7 are generated between movable contact member 1 and stationary contact members 3 and 4, respectively, as a result of the movement of the movable contact member 1. The electric arcs 6 and 7 are pushed into two long tubelike outlet channels 8 and 9 where they are subjected to the intensive flow of the quenching medium; first to a transverse flow and then to a longitudinal flow.

In order to guide the arc safely into the tubelike outlet channels 8 and 9, guiding electrodes 10 and 11 are disposed at the stationary contact members,-switching components 3 and 4. The guiding electrodes simultaneously serve as burnup pieces.

Additionally, magnetic coils 23 can also be connected to the stationary switching components 3 and 4 to produce a magnetic force in the direction opposite to the flow of the quenching medium, thus to impede expansion of the electric arc and to increase the voltage drop at the arc.

According to FIG. Ia the outlet channels 8 and 9 have a circular shape near the electrodes 1 and 10 or 1 and 11 respectively with one dimension increasing in the direction of the flow of the quenching fluid, thus providing an oval shape at the outlet openings. By this means the outlet openings point in different directions and prevent thereby the contact of ionized decomposition products originated by arcs in adjacent channels. FIG. in shows also the arrangement of magnetic coils 23 producing a magnetic force in the direction opposite to the flow ofthe quenching medium.

According to FIG. 2, three series-connected circuit breakers 20, 21, 22 are arranged parallel with respect to each other in the housing together with their movable contact members and their stationary contact members or switching components. The current connections are marked 13 and 14. Strong connecting sections 15 provide conductive paths between the stationary contact member 3 of the center circuit breaker 21 and the contact member 4 of the outside circuit breaker 20 as well as the stationary contact member 4 of the center circuit breaker 21 and stationary contact member 3 of outside circuit breaker 23. The guide electrodes 10 and II are connected to the switching components 3 and 4. A nozzletype opening is marked 5 which extends into an enlarged portion 16. FIG. 2 indicates the advantageous manner in which the circuit breaker according to the present invention can be constructed with small spatial dimensions in order to take care of circumstances where higher voltages are applied.

FIGS. 3a to 3d show another form of the movable contact member 1 according to the present invention. FIG. 3a shows a plan view while FIG. 3b shows a longitudinal view in section taken along the line 3b-3b of FIG. 3a. The movable contact member I of resilient material is divided into individual contact fingers 17 which contact the stationary contact members 3 and 4 at several points. FIG. 3d shows a longitudinal section through an electric arc quenching chamber of a circuit breaker having one movable contact member 1 according to FIG. 3a. In FIG. 3d the movable contact member l is in the switch-on position. The contact point of a finger 17 with the stationary contact piece 4 is marked 18. FIG. 30 shows the position of the connecting bridge during a cutoff period. The movable contact member is so constructed that, upon being moved away from the contact point 18, the contact fingers 17 further provide contacts at point I9. Since it is at the point 19 that the electric arc is initiated, this arrangement has the advantage of protecting against the premature wearing out of contact points 18, which carry continuous current, by the generated electric arc. All other portions of the quenching chamber correspond to those of FIG. 1. This form of the movable contact member I provides a make-before-break contact member. By this term is meant a contact which is so designed that the contacting surface, which serves to transmit the continuous or operating current, is not touched by the electric arc and is protected against damage. The electric arc is produced, both during switching on and switching off, at a point which protrudes above the above-mentioned contacting surface. This point is to have a shorter distance from the fixed counter contact during the switchingon and switching-off movements than the continuous current contact surface, so that the electric are always tends to jump over at this shorter point.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations.

We claim:

1. A circuit breaker, comprising, in combination:

an electric arc quenching chamber;

two spaced stationary contact members disposed within said chamber;

a movable contact member in said chamber for electrically connecting said stationary contact members in a first position thereof and for electrically disconnecting said stationary contact members when said movable contact member is moved toward a second position thereof, whereby electric arcs are formed in one general direction when said movable contact member is moved toward said second position;

means for introducing a stream of electric arc-quenching liquid into said chamber in a direction transverse to said general direction and for moving said movable contact member into said second position and retained there only by the direct impingement of the quenching liquid on said movable contact member; and

a plurality of tubelike outlet channels arranged for receiving said quenching liquid and extending in the direction of movement of said movable contact member so that the quenching liquid when moving into said chamber drives the electric arcs into said outlet channels.

2. Circuit breaker as defined in claim 1 wherein the movable contact member is forced into contact with said stationary contact members only by spring means provided therefor, the force of which spring means being overcome by the force of the quenching liquid for moving said movable contact member into its second position.

3. Circuit breaker as defined in claim 2 wherein the cross sections of said outlet channels increase in the direction away from where said electric arcs originate and in the direction of the flow of said quenching liquid.

4. Circuit breaker asdefined in claim 3 wherein said outlet channels have outlet openings which point in different directions.

5. Circuit breaker as defined in claim 4 wherein an electrode means is associated with each of said stationary contact elements, said electrode means being in contact with the associated stationary contact member and being at one end of said tubelike channel between said stationary contact member and said movable contact member.

6. Circuit breaker as defined in claim 5 further comprising magnetic force means arranged in such a manner that a magnetic force emanating therefrom will act on said electric arcs in a direction opposite to that in which the stream of quenching liquid flows in moving said movable contact member.

7. Circuit breaker apparatus wherein several circuit breakers as defined in claim 6 are disposed in a housing and the stationary and movable contact members, respectively, of said circuit breakers are arranged parallel with respect to each other, and said circuit breakers are electrically connected in series.

8. Circuit breaker as defined in claim 6 wherein said movable contact member includes a plurality of separated resilient contact finger elements which are pressed against said stationary contact members upon said movable contact member being brought into contact therewith.

9. Circuit breaker as defined in claim 8 wherein said movable contact member is a make-before-break contact member. 

1. A circuit breaker, comprising, in combination: an electric arc quenching chamber; two spaced stationary contact members disposed within said chamber; a movable contact member in said chamber for electrically connecting said stationary contact members in a first position thereof and for electrically disconnecting said stationary contact members when said movable contact member is moved toward a second position thereof, whereby electric arcs are formed in one general direction When said movable contact member is moved toward said second position; means for introducing a stream of electric arc-quenching liquid into said chamber in a direction transverse to said general direction and for moving said movable contact member into said second position and retained there only by the direct impingement of the quenching liquid on said movable contact member; and a plurality of tubelike outlet channels arranged for receiving said quenching liquid and extending in the direction of movement of said movable contact member so that the quenching liquid when moving into said chamber drives the electric arcs into said outlet channels.
 2. Circuit breaker as defined in claim 1 wherein the movable contact member is forced into contact with said stationary contact members only by spring means provided therefor, the force of which spring means being overcome by the force of the quenching liquid for moving said movable contact member into its second position.
 3. Circuit breaker as defined in claim 2 wherein the cross sections of said outlet channels increase in the direction away from where said electric arcs originate and in the direction of the flow of said quenching liquid.
 4. Circuit breaker as defined in claim 3 wherein said outlet channels have outlet openings which point in different directions.
 5. Circuit breaker as defined in claim 4 wherein an electrode means is associated with each of said stationary contact elements, said electrode means being in contact with the associated stationary contact member and being at one end of said tubelike channel between said stationary contact member and said movable contact member.
 6. Circuit breaker as defined in claim 5 further comprising magnetic force means arranged in such a manner that a magnetic force emanating therefrom will act on said electric arcs in a direction opposite to that in which the stream of quenching liquid flows in moving said movable contact member.
 7. Circuit breaker apparatus wherein several circuit breakers as defined in claim 6 are disposed in a housing and the stationary and movable contact members, respectively, of said circuit breakers are arranged parallel with respect to each other, and said circuit breakers are electrically connected in series.
 8. Circuit breaker as defined in claim 6 wherein said movable contact member includes a plurality of separated resilient contact finger elements which are pressed against said stationary contact members upon said movable contact member being brought into contact therewith.
 9. Circuit breaker as defined in claim 8 wherein said movable contact member is a make-before-break contact member. 